1785-LT

Overview

The 1785-LT is an Allen-Bradley PLC-5 controller module designed for programmable control systems with a capacity for both local and remote I/O expansion.

General Information

• Manufacturer: Allen-Bradley

• Part Number: 1785-LT

• Product Description: PLC5 Classic Programmable Controller

• Module Type: Processor

• Battery: 1770-XY

I/O Capacity & Expansion

• Supported Local I/O: Up to 4 Racks (1 resident rack)

• Supported Remote I/O: Up to 3 Remote I/O racks

• I/O Capacity: 512 I/O (512 inputs and 512 outputs using 16 or 32-pt modules)

• Max Total I/O: 3072 (any mix) or 3072 in + 3072 out (complementary)

• Analog I/O: 512

• Max Analog I/O: 3072

Memory & Performance

• Embedded RAM: 6K Words (expandable up to 14K Words)

• Memory Modules:

• 4K RAM expansion: 1785-MR

• 8K RAM expansion: 1785-MS

• 8K EEPROM: 1785-MJ

• Program Scan Time:

• 2 ms/K words (bit logic)

• 8 ms/K words (typical)

• Number of Words: 6 Kilowords SRAM (expands to 14 Kilowords)

Communication & Ports

• Built-in Communication:

• One standalone scanner (local and remote I/O) adapter

• One DH+ channel

• RS-232-C/422-A/423-A Ports: 1

• Control Coprocessor Expansion Port: Yes

Addressing & Mounting

• Hardware Addressing:

• 2-slot, 1-slot, ½-slot

• Location: 1771-I/O chassis, left-most slot

• Keying: Between 40 and 42; between 54 and 56

I/O Scan Time

• I/O Scan Time Per Rack:

• 10 ms at 57.6 kbits/s

• 7 ms at 115.2 kbits/s

• 3 ms at 230.4 Mbits/s

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